Conventional wood pallets include a base layer and a cargo layer separated therefrom by support blocks. Traditionally, the base and cargo layers respectively have end deck boards assembled on connector boards that run the full length or width of the pallet. The end deck boards are nailed through the connector boards into the support blocks to build the primary structure of the pallet. The end deck boards are also known as lead boards, and the connector boards are also known as stringer boards.
To move the wooden pallets with cargo thereon, forklift tines are inserted into the gaps between the base and cargo layers. If the forklift is not stopped in time, the forklift crashes into one of the end deck boards of the pallet. Impacts such as this weaken the pallet and greatly shorten the lifespan of the pallet, thereby causing the pallet to be repaired more frequently and/or removed from service before its anticipated life cycle has been reached.
In an effort to improve pallet durability, nail plates have been used to strengthen wood pallet joints. U.S. Pat. No. 7,056,074 to Bas discloses nail plates between an upper surface of the support blocks and boards in the cargo layer, and between a lower surface of the support blocks and boards in the base layer. Each nail plate includes projections extending from upper and lower surfaces thereof, and a center opening for receiving a connecting device. A respective connecting device is used for each support block to couple the corresponding boards in the cargo and base layers to each support block, with the corresponding nail plates penetrating into opposing wood surfaces.
Similarly, U.S. Pat. No. 6,584,915 to Rogers discloses nail plates to strengthen wood pallet joints. The nail plates are between the end deck boards and the support blocks, wherein the projections from the nail plates are embedded into the support blocks. In particular, the projections for each nail plate are grouped into two bands to leave a central or median region that is void of any projections. Nails are driven through the central or median region of the nail plates.
Yet a further use of nail plates is disclosed in U.S. Pat. No. 7,516,705 to Hedstrom. The '705 patent is assigned to the current assignee of the present invention, and is hereby incorporated by reference in its entirety. The nail plates are between the connector boards and the support blocks, wherein the projections from the nail plates are embedded into the connector boards.
Even in view of the above noted nail plates, there is still a need to further improve the resiliency of a wooden pallet to impacts from material handling equipment.